Latest: New York attack was in planning for weeks and was done 'in the name of ISIS'

Authorities have said Saipov left a handwritten note referring to the Islamic State group.

Update 3.50pm: The driver in New York's deadly vehicle bombing had been planning it for weeks and did it "in the name of Isis", a New York police department official has said.

Deputy Commissioner John Miller made the remarks at a briefing on Wednesday by city, state and US federal officials.